I've just spend the last ~4 hours seeing if i could find sounds matching the menacing roar of the Drones from Oblivion and even tried my hand at cutting the sound from the movie itself (with very poor results).

Here an example of the sounds, though keep in mind that these were ripped by someone using a CamRip of the movie, so the quality is far from what I'm looking for: https://www.youtube.com/watch?v=Mz491UK6_0c

I would really appreciate some help in either finding 10+ sounds relatively alike, or if someone could put such 10+ sounds together. ^_^